Every hour the root site writes a fresh timestamp somewhere in the archive; mirror sites copy this timestamp when they update the mirror archive. Mirmon periodically retrieves these timestamps from the mirror sites. It generates a html report and a flat state file.

Mirmon's actions and report are directed by a config file. There are many configuration parameters, but most have acceptable defaults. Only a few project specific items need to be specified. Once configured, mirmon can be run by cron every hour.

Mirror sites are probed at certain (user defined) intervals (default every 4 hours). Sites that are (temporarily) unreachable are probed more often (by default hourly) until a probe is successful.

The state file has a simple format and can be used for other administrative purposes (mailing admins of stale mirrors, directing users to fresh mirrors, etc).